It takes awhile to go through the TIGHAR database and other materials and it's interesting although I believe any post crash comm claims are bogus.
On that website there are reports of several people hearing transmissions many days later in the US on 1930s consumer units. The conclusions were they heard harmonics from the Western Electric
model 13 c aircraft transmitter. The antenna had been modified and both Earhart and her companion had limited understanding of radio. There are many intertwined variables so....
The bottom line I assume he is checking out if these claims are legit.
The Lady "Betty" claimed to have heard them at 18 mhz to 30 mhz. She had a Zenith Strat 1000z , which would have been tops and capable of hearing weak signals, only rich people would own.. There weren't many made.
The Lady" Nina "claimed she used a Philco console which generally ran up to 18 mhz but no more on their all-waves. Some of her claims in later years were termed "embellished" The Philcos were good radios but I don't think there are claims of sensitivity in terms of modern radios.
No one claimed to hear at 6210 or 3 mhz .
. The crash was in July.
I think they went into deep water and the radio quit then. I understand he is exhausting leads but isn't much scientific control there .
I'm not sure if he's with this org, didn't say
https://tighar.org/Projects/Earhart/Archives/Research/Bulletins/30_BettyHarmonic/30_Bettyharmonic.html I think the SWLs of 1937 made it up based on news reports,+ I mean on a Z 1000 n all (get real) that alone makes the story suspect right there but I guess he wants to disprove or leave it open.
I guess.
But Yo , I'm gonna check it.